Access ports are widely used in medical procedures to gain access to anatomical cavities ranging in size from the abdomen to small blood vessels, such as veins and arteries, epidural, pleural and subarachnoid spaces, heart ventricles, and spinal and synovial cavities. The use of access ports has become more common as they provide minimally invasive techniques for establishing a portal for a number of procedures, such as those involving the abdominal cavity.
A trocar is one type of access post that is commonly used to provide a minimally invasive pathway for accessing a surgical site. Trocars generally include a cutting assembly or obturator that is disposed within an outer cannula. The sharp distal end of the cutting assembly, with the cannula disposed therearound, is urged through the skin until it enters the anatomical cavity being penetrated. The cutting assembly is then withdrawn from the cannula, which remains in place to provide a passageway through which access to the anatomical cavity is provided for other surgical devices, e.g., laparoscopic instruments such as graspers, dissectors, scissors, retractors, etc.
While effective, there can be many disadvantages when using a typical trocar assembly. For example, numerous types of procedures using a typical trocar assembly involve insufflation of the abdominal cavity with CO2 gas to increase interior space for a surgical procedure. This is often achieved using an additional port to allow gas to be passed into a body cavity to provide pressure therein to maintain insufflation of the cavity. Maintaining insufflation can be difficult because the trocar can extend a distance above the skin and surface through which it is inserted depending on the length of the trocar, which could create a gap through which insufflation fluid can escape. Additionally, the trocar could move relative to the tissue in which it is inserted, such as when instruments are inserted therethrough into the cavity, which could affect insufflation as well as interfere with proper positioning of the instruments. Insufflation can be made even more difficult before the body cavity is inflated as there are organs and other vital structures that can be directly adjacent the puncture site where the trocar assembly is inserted through the tissue, and it is desirable to prevent damage to these structures during insertion of the trocar.
Accordingly, there is a need for improved methods and devices for providing access through tissue to a surgical site.